Adhesive tapes of various types are supported on a carrier web and released from such web upon dispensing. An example is the markers used in the audio and video recording industries. Such marker tape segments may be one-inch strips of polyester film about 0.7 mils thick, having an aluminized coating and a layer of pressure-sensitive adhesive. Such segments may be supported end-to-end on a carrier web which is a strip of polyester film about 2 mils thick.
Dispensing packages for such tape include an enclosure for a tape roll and a tape exit channel extending from the enclosure to an opening at the edge of the package. At or near the end of the tape exit channel is a relatively sharp edge across the channel which serves as a means to allow the user to separate the tape segments from the carrier web.
Such relatively sharp edge allows separation of the tape segments from the carrier web without the need to pick the segments off by hand, in the well-known manner hereafter described. Avoiding hand and finger contact with the adhesive-bearing surface of the segments is considered important. It is well known that hand contact can contaminate the adhesive, and that such contamination is detrimental because the adhesive is used for securing the aluminized tape segments to the magnetic tape.
By running the carrier web (with segments thereon) over the edge, the carrier web bends sharply around the edge while the segments do not. This causes the segments to progressively separate from the carrier web. Such separation facilitates, again without the need to pick the segments off by hand, the accurate application of tape segments onto the magnetic tape on which they will serve as markers.
When the tape advance and segment separation has progressed to a point where about three-fourths of an individual segment has separated from the carrier web, the tape segment is positioned, without hand or finger contact, over the desired area of attachment, usually at a specific point on magnetic tape. The segment is then pressed into tight engagement with the magnetic tape by finger pressure. Thereafter, the remainder of that segment is withdrawn from the package and pressed into tight engagement with the magnetic tape.
In order to be able to use this application technique successfully, it is necessary that the carrier web and its attached tape segments be taut as they approach the edge around which they will be pulled. Thus, a significant restraining force must be applied to the tape in the package, either by finger pressure through the package or by the package itself.
If sufficient restraining force is not maintained during the dispensing step, the tape cannot be pulled tightly around the edge. Furthermore, the tape may advance too far during the tape withdrawal action--such that the front end of the tape segment following the one being dispensed will be too far out for later proper dispensing. At that point, the segment has to be manually removed from the carrier web, with all the attendant disadvantages of manual removal.
Efforts have been made in the prior art to develop packages for dispensing tape segments carried on a carrier web. In particular, dispensing packages have been developed which include means to restrain the dispensing of tape in order to improve the tape separation and application process described above.
Included in the prior art are U.S. Pat. No. 3,743,086 (Aldrich) and U.S. Pat. No. 4,279,359 (Arnold). These patents describe so-called "blister packs" that comprise a thermoformed plastic cover element having a surrounding flange that is heat sealed or otherwise adhered to a flat base member, typically a cardboard card.
The Aldrich package attempts to restrain the dispensing of tape by applying pressure to the tape as it moves through the exit channel. However, as recognized in the prior art, it is very difficult, at least with certain kinds of tapes, to obtain proper restraining force in this manner. The Arnold patent applies restraining force in a different manner--by providing a dentate hub which engages the inner diameter of the tape roll such that its rotation is restrained. This in turn restrains the dispensing of tape from the package.
The latter means for restraining tape dispensing functions better than the former. But when the tape has left the roll but is still inside the package, the absence of good restraining pressure on the tape makes proper dispensing difficult, particularly if the tape has advanced too far, as frequently is the case. Unless the tape can be rewound, the restraining force imposed by the tape roll hub within the package is lost.
Another problem with prior tape-dispensing packages is that the supposedly sharp edge around which the tape is pulled is not sharp after the packages has been used for a period of time. The card which provides the edge may become frayed or otherwise damaged such that a sharp edge is not available.
There are significant problems and deficiencies in the tape-dispensing packages of the prior art. There is a need for a tape-dispensing package having improved tape-restraint characteristics on tape which is off the roll but still within the package, that is, which more reliably imposes a restraining force on tape within its exit channel. There is a need for a tape-dispensing package which more easily allows rewinding such that tape segments need not be removed from the carrier web by hand. There is a need for a tape-dispensing package which may readily be opened and reclosed.
There is a need for a package which may be reopened and reclosed, yet still has a exit channel which imposes significant restraining force on the movement of tape within the channel. And, there is a need for a tape-dispensing package having a lasting edge which will allow effective tape-segment separation over the life of the package. More generally, there is a need for an improved thermoformed package which may be made from a single thermoformed sheet. There is a need for a simple reclosable package which may be reliably and tightly closed.